Dental apparatus

ABSTRACT

Dental apparatus including a housing with an amalgam container therein and means expelling amalgam from its container into a receiver chamber, means ejecting the amalgam from the receiver chamber into a tooth cavity, the ejecting means including a packer member that forces the amalgam into the tooth cavity and packs the amalgam in the cavity.

I United States Patent [191 1111 3,792,530

Smith Feb. 19, 1974 DENTAL APPARATUS 2,837,824 6/1958 Moller 32/60 [76] Inventor: 7 Donald G. Smith, 6915 Red Rdfi,

C G m F1 33143 FOREIGN PATENTS OR APPLICATIONS Filed: Feb. 1967 309,333 4/1929 Great Britain 32/60 [21] Appl. No.1 628,192

- Primary ExaminerLawrence W. Trapp Related Apphcatmn Data Attorney, Agent, or Firm-Shoemaker and Mattare [63] Continuation-impart of Se'r. No. 200,398, June 6,

I962, abandoned.

[30] Foreign Application Priority Data 57 STR C June 12, 1961 Great Britain 21130/61 Dental apparatus including a housing with an amalgam [52] US. Cl 32/54, 32/60, 32/56 container therein and means expelling amalgam from [5i] Int. Cl A616 3/08 its container into a receiver chamber, means ejecting [53] Field Of Sear h 32/26; 27, 0, the amalgam from the receiver chamber into a tooth 32/60 cavity, the ejecting means including a packer member a that forces the amalgam into the tooth cavity and [56] References Cited packs the amalgam in the cavity.

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ATTORNEYS PATENTEDFEB1 91974 3,792. 530- SHEET 10 OF H INVENTOR ATTORNEYS v DENTAL APPARATUS The present application is a continuation-in-part of abandoned U. S. Pat. application Ser. No. 200,398, filed June 6, 1962.

The present invention relates to dental apparatus, and more particularly to dental apparatus to be used in connection with a filling of a tooth cavity.

The present invention is concerned with several aspects of the procedures employed in filling a tooth cavity.

Firstly, the present invention is directed to a dental amalgam unit which is a self-contained pre-packaged unit which may be readily stored and which includes the unmixed necessary ingredients to provide a finished dental amalgam. In the prior art, the ingredients for preparing the finished amalgam are separately packaged and provided whereupon the dentist or his assistant must take these separate ingredients and mix them in the proper proportions, and must then carefully mix these ingredients according to certain prescribed procedures in an effort to obtain uniform results. As a practical matter, it is virtually impossible for a person to exactly duplicate this type of process, and accordingly dental amalgams are obtained of inferior quality even when a great degree of skill is employed in mixing the ingredients of the finished amalgam.

The self-contained pre-packaged unit of the present invention overcomes many of the problems encountered in mixing dental amalgams in the prior art by providing the-unmixed ingredients in the exact desired proportions, and further the construction is such that the unit can be manually manipulated so as to cause mixing of the ingredients when desired without actually touching the ingredients whereupon the finished dental amalgam may be employed in filling a tooth.

The present invention also contemplates a dental amalgam cartridge which also is a self-contained, readily stored pre-packaged unit having the unmixed necessary ingredients therein for providing a finished amalgam. This cartridge provides the same advantages as discussed above in providing high quality uniform batches of finished amalgam requiring no special skill on the part of personnel employing the invention.

The cartridge of the present invention is also specifically designed to be employed with a novel mixing device which ensures that optimum results are obtained in mixing the ingredients to provide the finished amalgam. 1

Still another feature of the novel cartridge of the present invention is the fact that it is adapted to be mounted in a novel dental instrument employed for filling teeth and compacting the amalgam in the tooth. This cartridge affords a ready means for loading amalgam into such instrument and is of such a construction as to permit the amalgam to be properly fed to the working tip of the instrument hereinafter described.

The present invention also relates to a unique mixing device for mixing the ingredients ofa cartridge as discussed above. This mixing device incorporates a novel construction which is adapted to squeeze the side walls of the cartridge while compressingthe contents thereof to retain the shape and size of the cartridge. This is an important feature since the cartridge according to the present invention is formed of a somewhat flexible material such as plastic or the like which is adapted to be thrown away after use. Accordingly, it is necessary to apply such squeezing action to the outer walls of the cartridge while compressing the contents thereof so that undesirable distortion does not occur.

The mixing device of the present invention also includes means for vibrating the cartridge and its contents while the amalgam ingredients are being mixed and compressed so as to ensure effective mixing of the amalgam components.

The cartridge means of the present invention includes first and second container means, and the mixing device incorporates means for removing the inner: container means of the cartridge after mixing so that the cartridge is then ready for usein a dental instrument.

The present invention further is directed to a novel dental instrument adapted to perform a dual function. When it is necessary to fill a cavity in a tooth with filling material such as a silver amalgam material, the material must first be inserted into the cavity of the tooth and then compacted into the cavity so that it is fully filled. This compacting results in greater hardness of the amalgam and eliminates voids therewithin. This is most effectively accomplished by providing forceful blows or impacts to the amalgam when in the cavity in the tooth. In the prior art, different instruments are employed for carrying out these operations. Furthermore, additional filling material may be required tobe inserted in the cavity from time to time and the dentist or his assistant has to carry this additional filling material from its place of preparation to the patient.

These operations as carried out in the prior art necessitate the use of different dental instruments and a considerable amount of time is spent in changing from one instrument to another.

In the present invention, the dental instrument is adapted to perform the dual function of inserting the amalgam material into the cavity in a tooth and also to compact the amalgam after it is inserted into the cavity.

The instrument of the present invention includes means for readily filling or refilling the instrument with a dental amalgam material as required.

The instrument of the present invention employs a working tip having a bore formed therethrough, this...

working tip being adapted to extend into the cavity in a tooth. This arrangement will prevent excessive penetration of amalgam material over the good part of the tooth and will prevent actual contact of the vibrating compacting member with the tooth since the vibrating compacting member travels through this hollow working top during operation of the apparatus.

Power-operated means is provided for operating the plunger of the present invention which serves both to move the material through the working tip and to compact it after being inserted in place. Additionally, novel feed means is provided for forcefully feeding amalgam material to the working tip and the plunger so that a substantially continuous filling and compacting operation may be carried out thereby resulting in a considerable saving in time and effort on the part ofthe dentist.

An object of the present invention is to provide a selfcontained pre-packaged dental amalgam unit including the unmixed necessary ingredients to provide a finished amalgam and wherein this unit is of such construction as to be effectively manually manipulated so as to mix the ingredients together when desired to provide batches of amalgam of uniform high quality without requiring any special skill on the part of personnel employing the unit.

Another object of the invention is to provide a cartridge which is of a self-contained pre-packaged construction including the unmixed necessary ingredients to provide a finished amalgam of uniform high quality, and wherein this cartridge is of such a construction as to be readily employed with a novel mixing device to provide the finished amalgam.

A further object of the invention is to provide a dental amalgam cartridge which is adapted to be mounted in a dental instrument employed for filling teeth and compacting the amalgam within a tooth.

Still another object of the invention is the provision of a novel mixing device especially adapted to mix the ingredients supported within a dental amalgam cartridge and including means for retaining the shape and size of the cartridge while mixing the ingredients thereof.

Yet another object of the invention is to provide a mixing device as set out in the previous object including means for vibrating the cartridge while the contents thereof are under compression to ensure effective mixing and further which includes means for removing the inner container means from the cartridge after mixing.

Another object of the invention is the provision of a dental instrument serving the dual function of inserting dental amalgam into the cavity in a tooth and compacting the amalgam after having been so inserted, thus reducing the number of different instruments required.

Still another object of the invention is to provide a dental instrument including means enabling ready filling and refilling of the instrument with amalgam material as required and which further prevents excessive penetration of the amalgam material over the good part of the tooth and prevents actual contact of the vibrating compacting member with the tooth being filled.

A further object of the invention is the provision of a dental instrument which is very compact and relatively simple and inexpensive in construction, and yet which at the same time is quite efficient and reliable in use.

Other objects and many attendant advantages of the invention will become more apparent when considered in connection with the specification and accompanying drawings, wherein;

FIG. 1 illustrates a part-sectional side elevation of a dental instrument according to the invention;

FIG. 2 illustrates a perspective view of part of the instrument housing and a working tip therefor;

FIG. 3 illustrates a part-sectional side elevation of a further dental instrument according to the invention;

FIG. 4 illustrates a sectional side-elevation of a part of the instrument illustrated in FIG. 3;

FIGS. 5, 6 and 7 each illustrate perspective views of different types and shapes of working tips for use in the instruments illustrated in FIGS. 1, 3 and 4;

FIG. 8 is a longitudinal section through a dental amalgam unit according to the present invention;

FIG. 9 is a sectional view taken substantially along line 9-9 of FIG. 8 looking in the direction of the arrows;

FIG. 10 is a view similar to FIG. 8 illustrating the manner in which the inner container means is broken so as to mix the ingredients of the unit;

FIG. 11 illustrates the manner in which the unit may then be employed for filling a storage cavity or the like with the finished amalgam;

FIG. 12 is a longitudinal section through a dental amalgam cartridge according to the present invention;

FIG. 13 is a sectional view taken substantially along line 13-13 of FIG. 12 looking in the direction of the arrows;

FIG. 14 illustrates a longitudinal section through a cartridge similar to that shown in FIG. 12 with a modified bottom wall portion;

FIG. 15 is a view similar to FIG. 14 illustrating still another form of bottom wall portion for the cartridge;

FIG. 16 is a top perspective view of a novel amalgam mixing device according to the present invention;

FIG. 17 is a sectional view taken substantially along line 1717 of FIG. 16 looking in the direction of the arrows;

FIG. 18 is a view taken substantially along line 18-18 of FIG. 17 looking in the direction of the arrows;

FIG. 19 is a sectional view taken substantially along line l9-19 of FIG. 17 looking in the direction of the arrows;

FIG. 20 is an enlarged sectional view showing the lower portion of the mixing device illustrated in FIG. 17 and illustrating an initial step in the mixing of amalgam within a cartridge according to the present invention;

FIG. 21 is a view similar to FIG. 20 illustrating a further step in the mixing of amalgam within a cartridge according to the present invention;

FIG. 22 is a view similar to FIGS. 20 and 21 illustrating a further step in the use of the apparatus;

FIG. 23 illustrates a still further operative position of certain components of the mixing device;

FIG. 24 is a vertical section through a modified form of dental instrument according to the present invention;

FIG. 25 is a sectional view taken substantially along line 25-25 of FIG. 24 looking in the direction of the arrows;

FIG. 26 is a sectional view taken substantially along line 2626 of FIG. 24 looking in the direction of the arrows;

FIG. 27 is an enlarged sectional view taken substantially along line 27-27 of FIG. 26 looking in the direction of the arrows;

FIG. 28 is an enlarged sectional view taken substantially along line 2828 of FIG. 24 looking in the direction of the arrows;

FIG. 29 is a sectional view taken substantially along line 2929 of FIG. 28 looking in the direction of the arrows;

FIG. 30 is an enlarged sectional view taken substantially along line 3030 of FIG. 24 looking in the direction of the arrows; I

FIG. 31 is a sectional view taken substantially along line 3131 of FIG. 24 looking in the direction of the arrows;

FIG. 32 is a top perspective view illustrating a jig arrangement for filling the feed means of the apparatus illustrated in FIGS. 23 31 with dental amalgam material and for removing a flexible elongated feed member therefrom;

F I6. 33 is a sectional view taken substantially along line 3333 of FIG. 32 looking in the direction of the arrows and illustrating a bodymeans in place on the jig;

FIG. 34 represents a view taken substantially along line 34-34 of FIG. 32 and showing the manner in which a body means is received on the jig and the flexible feed member removed therefrom;

FIG. 35 is a longitudinal section through still another modified form of the dental instrument according to the present invention;

FIG. 36 is a section view taken substantially along line 36-36 of FIG. 35 looking in the direction of the arrowswith certain parts removed for the sake of clary;

FIG. 37 is an enlarged sectional view taken substantially along line 3737 of FIG. 36 looking in the direction of the arrows;

FIG. 38 is an enlarged sectional view taken substantially along line 3838 of FIG. 36 looking in the direction of the arrows;

FIG. 39 is a view illustrating the manner in which the plunger of the instrument is adapted to be extended beyond the outer end of the working tip for compacting the dental amalgam material within a cavity in a tooth;

FIG. 40 is a vertical section through a still further modified form of dental instrument according to the present invention;

FIG. 41 is a sectional view taken substantially along line 4l4l of FIG. 40 looking'in the direction of the arrows;

FIG. 41a is a top perspective view of the automatic air flow control means employed in the modification illustrated in FIGS. 40 and 41;

FIG. 42 is a longitudinal section through one end portion of still another modified form of dental instrument according to the present invention;

FIG. 43 is a longitudinal section through the opposite end portion of the dental instrument shown in FIG. 42;

FIG. 44 is a sectional view taken substantially along line 4444 of FIG. 43 lookingin the direction of the arrows; and

FIG. 45 is a view similar to FIG. 44 illustrating the components in a different operative position.

Referring now to the drawings wherein like reference characters designate corresponding parts throughout the several views, FIGS. 1 and 2 illustrate a dental instrument for applying a filling material to a tooth cavity, comprising a longitudinally extending housing 1 of annular cross-section. One end 2 of the housing 1 is smaller in diameter than the major part of the housing length and is shaped so as to extend for a short length at an angle of approximately 30 to the major longitudinal axis and then terminate in a further short length projecting towards the major longitudinal axis at an angle of approximately 90 to the first-mentioned short length. The said one end 2 is thus goose-necked in shape to form a convenient handle to the instrument, and is adapted and enlarged at an extreme portion 3 having a cavity adapted to receive and retain a dental working tip 4.

A central bore 5 of circular cross-section extends through the working tip and is in alignment with a bore in the housing through which extends a plunger 6 of circular cross-section. The plunger is connected to a flexible shaft 7 which is connected to a vibrator 8 to be driven thereby. Movement of the flexible shaft, and thus movement of the plunger along the bore 5 in the working tip, is controlled by a finger push-knob 9 ex tending along the outside of the main housing. A spring 10 is provided to keep the plunger in the inner extremity of the bore 5 in the working tip until moved forward by the operation of the push-knob.

The vibrator 8 is electrically driven, but it will be appreciated that it may alternatively be driven by air, by water or by mechanical means. A switch (not shown) is provided to switch the vibrator on and off.

The portion 3 (FIG. 2) of the housing is provided with a circular snap ring 11 and locating slots 12 (only one of which is shown).

The detachable working top 4 comprises a boss 13 having an external diameter such that it can fit tightly into the cavity in the enlarged portion 3 in the housing and has formed thereon a raised ring 14 together with four guiding pins 15 (only one of which is shown) for engaging in the said slots. Four slots are in fact provided in the portion 3 of the housing at to each other, and four corresponding pins are provided on the boss 13 of the working tip whereby the working tip can be turned to any one of four positions as required. A hollow tube 16 extends from, and is integral with, the boss 13, and when the tip is in position this tube extends from the end of the housing.

In use, the working tip 4 retained in the housing is pushed into a mass of filling material so that its core 5 is filled with this material. The tip is then applied to the tooth cavity to be filled and the finger knob 9 pushed so as to move the plunger forward and push the filling material out of the bore and into the tooth cavity. The vibrator 8 is switched on and is operative during the whole of this step in the treatment and causes the plunger 6 to be vibrated backwards and forwards in the bore in the working tip. As the tooth cavity becomes full and vibration of the plunger causes the filling material to be compacted in the tooth cavity, first through the medium of the filling material still in the bore of the working tip and then directly on the material in the tooth cavity when the bore is cleaned. The plunger 6 is arranged to be vibrated and pushed forward to the open end of the bore 5 in the in tip but notbeyond it. The speed of movement of the plunger along the bore is determined by the speed of movement of the push-knob. I

To refill the working tip 4 the push-knob is released so that the plunger is retracted along the bore 5. The working tip can then be re-filled by pressing it into the filling material again.

Referring now to FIGS. 3 and 4 there is illustrated another embodiment in which a main housing is provided which is similar tin shape to that illustrated in FIG. 1 except for the provision of a reservoir cavity 18.

A pivoted reservoir container 19 having a grooveshaped, e.g., U-shaped cross-section is housed in this cavity and can be swung down, filled with the toothfilling material and swung back into position again. The reservoir cavity 18 communicates with the end 2 of the housing through a tubular member 20 which extends across the goose-necked part and opens into the cavity in the portion 3 of the housing. Side flanges may be provided between the tubular member 20 and the housingfor increasing the rigidity of the structure.

A detachable working tip 21 is provided in this case with a number of auxiliary bores 22 each at right angles to its central bore 5, and when the working tip is in one of its operative positions an auxiliary bore is always caused to be in-line with the bore in the tubular member 20. Filling material can thus pass from the reservoir container in the cavity 18 to the central bore in the working tip.

Instead of providing slots in the end 3 of the main housing and corresponding pins on the working tips, a plurality of studs 23 are provided in the internal surface of the cavity in the end 2 and a like plurality of cavities 24 are provided on the working tip for engagement with the studs.

An auxiliary plunger 25 is providedin the housing and is capable of being moved along the groove in the reservoir container to force filling material out of the reservoir container along the bore in the tubular member and into the central bore 5 in the working tip. The auxiliary plunger is continuously urged by an auxiliary spring 26 to force material out of the reservoir container, but a projection 9a on the push-knob 9 causes a rotatable cam 9b to engage with ratchet teeth 27 formed in a rod 28 attached to the auxiliary plunger whereby movement of the auxiliary plunger 25 is prevented until the main plunger 6, which moves in the bore 5 in the working tip, is retracted by releasing the finger pressure applied to the push-knob 9.

The plunger rod 28 is provided with a laterally extending knob 29 protruding through the housing to enable the plunger 25 to be pushed back against the action of the auxiliary spring for re-loading the reservoir container.

In use, filling material can be inserted into a tooth cavity and compacted as in the previous embodiment. If more filling material is required, the push-knob 9 is released to retract the main plunger 6 and the auxiliary plunger 25 then forces filling material out of the reservoir container into the central bore 5 of the working tip. The filling of the cavity and compacting of the material can then be carried on.

The reservoir container 19 may extend partly round the housing 1 to facilitate its re-loading, instead of fitting wholly in the reservoir cavity, and it may be removable from the main housing to facilitate re-loading and- /or cleaning.

It will be appreciated that the instrument may be provided with a plurality of interchangeable working tips all having central bores of different cross-sectional shapes and dimensions together with a plurality of interchangeable main plungers of different cross-sections and movable in the central bore of corresponding cross-section in the working tips.

For example, in FIG. 5 there is shown a plunger 30 which is trapezoidal in cross-section and is movable in a tip 4 having a trapezoidal bore 31.

In FIG. 6 there is shown a plunger 32 which is circular in cross-section and is movable in a tip 4 having a circular bore 33.

In FIG. 7 there is shown a plunger 34 which is kidneyshaped in cross-section and is movable in a tip 4 having a kidney-shaped bore 35. The tips illustrated in both this figure and FIG. 6 are adapted for use in the instruments illustrated in FIGS. 3 and 4. The provision of different shaped plungers is useful when cavities of different shapes and sizes are to be filled with the filling material. The plunger rod in each case may be made of nylon or a plastic material for flexibility and to enable the working tip to be rotated to other positions to suit the shape of the cavity, and it may even be rotated through 360.

The frequency of the vibrator may be only two or three cycles per second. Alternatively, it may be an ultrasonic frequency or any frequency below this.

The vibrator may of course, be variable so as to vary the rate of vibration of the plunger and the length of its stroke by using a suitable control means on the main housing. Alternatively, these operations may be set by the manufacturer.

The auxiliary plunger may also be connected to the vibrator if desired. This is of advantage if semi-solid filling material is used.

It will also be appreciated that the vibrator itself need not be within the main housing but may be external thereof.

The instrument may be so constructed that the constituent raw materials which make up the filling material may be triturated or mixed together in the dental instrument itself.

The working tip need not be detachable from the main housing but may be integral with it. This may be advantageous if high pressures are used, in which case the bore through the tip should preferably be of circular cross-section and of small diameter.

It will be appreciated that a dental instrument in accordance with the invention may be used for applying filling material to a tooth cavity and then, in the same hand motion the material may .be thoroughly condensed (compacted) into all parts and recesses of even the most complex cavities without the necessity of having to use another instrument and without withdrawing the instrument away from the cavity for re-loading.

Referring now to FIGS. 8 10 inclusive, a dental amalgam unit or capsule according to the present invention is illustrated. This unit is indicated generally by reference numeral 40 and includes a first outer container means 42 and a second inner container means 44. Each of these container means is formed of a suitable flexible material such as a relatively thin pliable nylon or other plastic and the like, the two containers each being completely closed and sealed with the inner container 44 secured to the outer container 42 along a portion 46 as by heat sealing or other suitable means for securing the two container means to one another.

The inner container means 44 includes a weakened portion 48 which actually comprises a wall portion of reduced thickness, this weakened portion being adapted to break before other portions of either the inner or outer container means.

The first container means 42 is substantially filled with a dental amalgam ingredient, and in this case, this ingredient may comprise a body of powder indicated generally by reference numeral 50, this powder being of the type as employed in conventional silver amalgams. The inner container means 44 is substantially filled with a dental amalgam ingredient, and in this case this comprises a body of mercury indicated generally by reference numeral 52.

It is apparent that when the unit is in the condition illustrated in FIG. 8 which representsthe completed manufactured article, the amalgam ingredients are separated from one another, and a self-contained readily stored prepackaged unit is provided wherein the amalgam ingredients are in an exact predetermined ratio with respect to one another.

Referring now to FIG. 10, the manner in which the unit is employed may be fully understood wherein the arrows indicate the manner in which pressure may be manually applied to the unit so as to squeeze the righthand end of the unit as seen in FIG. 10 thereby compressing the flexible inner and outer container means and applying sufficient pressure thereto so as to cause the weakened wall portion of the inner container to burst. When this weakened wall portion bursts, the contents of the inner container will be forced outwardly into the contents of the outer container thereby causing the mercury to mix with the powder. The unit may then be manipulated or massaged by hand or by inserting in into a conventional amalgam mixing device of the oscillating or vibrating type with the capsule and enclosed pestle causing a thorough mixing to give the finished amalgam. The outer container would be strong enough not to rupture. The initial bursting of the inner container could even by accomplished with this conventional oscillating capsule and pestle by simply inserting the unsqueezed pre-packaged unit directly into the conventional mixing capsule and then mixing in a conventional manner. It is apparent that with this arrangement batches of uniform high quality may be readily obtained and without requiring any special skill 'on the part of personnel using the unit.

Referring now to. FIG. 11, the manner in which the unit is employed is illustrated. As seen in this figure, the finished amalgam indicated by reference numeral 56 is being squeezed outwardly through a hole 58 which has been cut at one end of the unit. This finished amalgam is being squeezed into a storage means indicated generally by reference numeral 60, this storage means comprising a portion of a dental instrument, and the details of this storage means as well as the dental instrument are described hereinafter.

It will also be understood that the unit may of course be employed for providing finished amalgam for any type of procedure, and that this unit may as well be employed for providing finished amalgam for any type of dental procedure, and that the unit is not necessarily restricted for use with the dental instruments as described herein.

Referring now to FIGS. 12 and 13, a dental amalgam cartridge is illustrated and indicated generally by reference numeral 70. This cartridge includes a first container means 72 of a plastic material which is relatively rigid although slightly flexible, and this may be formed of nylon or a similar plastic. The container means72 includes a bottom wall portion 74 having a very small hole 75 formed therethrough, the container'including an open top portion 76 as illustrated in FIG. 12. A flange 78 extends radially outwardly from the upper end of container means 72 and extends peripherally around this open end. This flange is useful both in positioning the cartridge relative to a mixing device hereinafter described, and also for properly positioning the cartridge within a dental instrument.

A second container means 80 is provided, this container means being formed of a. flexible material such as nylon or the like, and includes a weakened wall portion 82 of diminished thickness,this wall portion being disposed at the underside of container means 80 as seen in FIG. 12. This container means is completely closed and sealed.

The first container means is partially filled with a dental amalgam ingredient indicated as a body of powder 84 similar to the powder 50 disposed within the dental unit previously described. 'As seen in FIG. 12, this body of powder is disposed adjacent the closed end 74 of container means 72 and only partially fills the container means so as to be spaced a substantial distance from the open end 76 of the first container means.

The second container means 80 is substantially filled with a second dental amalgam ingredient as a body 86 of mercury. This second container means is pressed into the position illustrated in FIG. 12 so as to have a tight fit peripherally therearound with the inner surface of the first container means whereby the second container means effectively acts as a stopper in the first container means so as to retain the body of powder 84 within the first container means. While container 80 is shown as being of generally oval configuration, it is apparent that it may be of any suitable shape as long as it fits snugly within the upper end of the container 72.

The complete article is illustrated in FIG. 12, and in use pressure is applied to the upper side of the second container means 80 as by means of a mixing device hereinafter described, thereby causing rupture of the weakened wall portion 82 of the second container means so that the mercury within the second container means can be mixed with the powder'in the first container means to provide a finished amalgam. Hole 75 in the bottom wall portion 74 of container 72 allows any enclosed air to be expelled from the container so that the mercury can be forced all the way down through the powder to the bottom of thecontainer so as to be thoroughly mixed. When the cartridge is subsequently employed in a dental instrument according to the present invention, the lower wall portion 74 is severed by a suitable means such as a sharp knife or the like so that the finished amalgam can be forced out of the cartridge.

Referring now to FIG. 14, a modification is illustrated wherein the cartridge is identical with that previously described except that the first container means 82 which correspondsto the first container means 72 previously described is provided with a lower wall por tion 94 having a concave configuration rather than a flat. lower surface as previously described and including a tiny hole 95 formed therethrough. A body of powder 96 is disposed within the cartridge in the same manner as previously described. i

Referring now to FIG. 15, a further modification is illustrated wherein the first container means 100 includes a bottom wall portion 102 which is of convex configuration having a tiny hole 103 formed there through, a body of powder 104 being disposed within the cartridge.

It will be noted that the cartridge may be provided .with lower wall portions of the first container means of comprises a self-contained readily stored pre-packaged unit having the unmixed ingredients in a specific predetermined ratio with respect to one another thereby enabling uniform batches of high quality to be readily prepared for use in a dental instrument.

Referring now to FIGS. 16 through 23 inclusive, a mixing device according to the present invention is illustrated, this mixing device being especially adapted for use with a cartridge of a construction similar to that shown in FIGS. 12 through inclusive.

The mixing device includes a base means 110 having a plurality of resilient support members 112 as seen in FIG. 17, these support members being formed of rubber or a similar material. The base means is provided with a tapered bore 1 14 which opens through the upper surface 115 of the base means, this bore tapering downwardly and inwardly as seen for example in FIG. 17.

A split collet means indicated generally by reference numeral 120 in FIG. 16 includes two similar portions 122 and 124 adapted to be initially disposed in spaced relationship to one another, these two members 122 and 124 including tapered side surfaces complementary to the tapered walls of bore 1 14 in the base means, members 122 and 124 having radially outwardly disposed flanges 122' and 124' disposed at the upper end thereof. A compression spring 126 is disposed in surrounding relationship to the collet members 122 and 124 and engages the undersurface of flanges 122 and 124', the compression spring resting on the upper surface 1 15 of the base means for normally urging the collet means in an upward direction.

As seen most clearly in FIG. 16, a disc-like support member 130 is provided, this disc-like member having a central bore 131 extending therethrough and including a peripheral shoulder portion 132 disposed within this bore. This shoulder portion 132 is adapted to receive and support the flange portion 78 on a cartridge 70 for supporting the cartridge within the support member. The outer periphery 134 of support member 130 is knurled to facilitate manual grasping thereof. This support member is adapted to rest on the flat upper surfaces of the collet members 122 and 124.

A bore 138 extends upwardly from the bottom of the base means and is in communication with the central lower portion of the tapered bore 114 in the base means. The lower end of bore 138 is threaded and receives a threaded plug 140 which supports a compression spring 142 having a ball 144 formed of steel or the like supported at the upper end thereof. This ball 144 is adapted to engage and support the lower wall of a cartridge supported within the collet means. Plug 140 includes an upwardly extending integral projection 146 of reduced dimension which fits within compression spring 142. The upper end of projection 146 is normally spaced slightly below ball 144. Projection 146 serves as a limit stop for downward movement of ball 144; and in a typical example, the upper end of the projection may be spaced approximately one thirty-second inch below the ball. This will permit sufficient downward movement of the ball to permit oil-canning" of the bottom of a cartridge supported by the apparatus.

As seen particularly in FIG. 16, apair of guide rods 150 and 152 extend upwardly from the upper surface 115 of the base means, these guide rods being slidably received within bushing means 158 and 160 provided in a crosshead 156, this crosshead being mounted for reciprocation vertically with respect to the guide rods.

The crosshead 156 is normally urged in an upward direction by suitable resilient means including a first compression spring 162 disposed in surrounding relationship to guide rod 150. This compression spring engages the undersurface of the crosshead and is supported upon a collar 164 fitted about guide rod and held in place by a set screw 166. A similar compression spring 168 is disposed in surrounding relationship to guide rod 152. The spring 168 engages the undersurface of the crosshead and rests upon a support collar 170 disposed in surrounding relationship to guide rod 152 and held in place by a set screw 172.

A pair of support members and 182 extend upwardly from the upper surface 115 of the base means. A handle portion 184 adapted to be manually grasped is connected to a portion 186 of a generally U-shaped yoke member including arms 188 and 190. The upper ends of support members 180 and 182 are bifurcated, and the outer ends of arms 188 and 190 are disposed within these bifurcated upper end portions of the support members 180 and 182 respectively, and are pivotally supported upon pivot pins 192 and 194.

The crosshead 156 includes outwardly extending lugs 200 and 202 which extend from opposite ends of the crosshead and are slidably received within slots 204 and 206 formed within the arms 188 and 190 respec tively. As illustrated in FIG. 16, the crosshead is in its upper limit of movement as determined by engagement of the lugs 200 and 202 with one end of the slots 204 and 206 respectively.

A bracket 210 is secured as by bolts 212 to the upper surface of the crosshead 156, bracket 210 serving to support a suitable drive means such as an electric motor 214. The motor 214 includes an output shaft 216 which is keyed to a member 218 disposed at the outer end of the output shaft. Member 218 includes an irregular outer surface 220 of generally sinusoidal shape for imparting vibrations to a pistonmeans hereinafter described. The outer surface of member 218 also includes an arcuate depressed cam portion 222 as seen particularly in FIG. 17 for a purpose hereinafter described.

A tubular support member 230 is fixed within a central hole provided in the crosshead 156, this support member 230 having an elongated bore 232 extending longitudinally therethrough. A piston means comprising a rod-like member 234 is slidably positioned within bore 232. The 'piston means includes a rounded upper end portion 236 adapted to engage the outer surface of member 218. A collar 238 is formed about thev upper portion of the piston means, and a compression spring 240 disposed within a recess 242 provided in support member 230 engages the undersurface of collar 238 for urging the piston means upwardly against the outer surface of member 218.

As seen particularly in FIG. 20, a recess 250 is provided in the lower surface of piston means 234, an inwardly extending wall portion 252 having a central hole formed therethrough being disposed adjacent recess 250, and a longitudinally extending bore 254 extending vertically upwardly from the wall portion 252.

A removing member 256 is provided, this member being of generally cylindrical configuration and having a sliding fit with the hole provided in the wall portion 252. Removing member 256 terminates in a sharpened lower end 258 of enlarged dimension, this end being disposed within the recess 250 in the lower end of the piston means.

At the upper end of removing member 256, a laterally extending arm portion 260 is provided which terminates in an enlarged portion 262 adapted to be manually engaged for operating the removing member. The laterally extending portion 260 extends through slots 264 and 266 provided in the wall portions of the piston means 234 and the support member 230 respectively.

A compression spring 270 is disposed within the bore portion 254 of the piston means and engages the undersurface of the laterally extending portion 260 of the removing member 256 for normally biasing the removing member upwardly into the operative position illustrated in FIG. 20.

When it is desired to mix the contents of a cartridge such as shown in FIG. 12 with the mixing device shown in FIGS. 16 through 19 inclusive, a cartridge is first mounted within the support member 130 as illustrated in FIG. 16 by dropping the cartridge into operative position, whereupon the support member and cartridge are placed in operative position with the support member disposed on the top of the collet means and with the cartridge extending down within the cylindrical bore defined between members 122 and 124 of the collet means, these rnembersbeing biased in an upward direction and separated from one another at such time.

The handle 184 is then grasped and swung downwardly about the pivot pins 192 and 194 so as to move the crosshead 156 downwardly against the force of springs 162 and 168. This of course moves the support member 230 and the piston means 232 downwardly so that the bottom surface of the support member 230 comes into contact with the upper surface of support member 130 as illustrated in FIG. 20. I

As seen in FIG. 16, a manually operable switch 274 is provided and is connected in an electrical circuit including the input leads 276 and leads 278 extending from the switch means to the electric motor 214. By actuating motor 214 after the crosshead has been moved downwardly, member'218 is rotated. As member 218 is rotated in a clockwise direction from that shown in FIG. 17, it will be apparent that the cam surface 222 will initially biasthe piston means 234 downwardly so as to move the piston means out of the lower end of the support member 234 so that the piston means will move downwardly to the position shown in FIG. 21. As the piston means moves downwardly, it applies pressure to the upper surface of the container means 80 of the cartridge so as to cause the undersurface of the cartridge which is weakened to rupture, and subsequently further pressure of the piston means in a downwardly direction causes the contents of container means 80 to be pressed outwardly therefrom while collapsing the container means. This is illustrated in FIG. 21 wherein the container means 80 has been collapsed and the mercury obtained therewithin has been urged downwardly into the powder supported within the container means 72.

Further rotation of member 218 in a clockwise direction as seen in FIG. 17 causes the upper end 236 of the piston means to travel over the irregular outer surface 220 of the member 218. This will cause vibrations of the piston means in cooperation with the spring means 240. This vibration of the piston means will of course be imparted to the contents of the container means 72 so as to ensure effective mixing of the amalgam ingredients.

While this vibration is taking place, the ball 144 which is resiliently supported by spring 142 will serve to resiliently support the bottom of the cartridge thereby permitting the desired vibrating effect to cause oil canning or deflection up and down of the bottom of the cartridge supported by the collet means thus allowing actual mixing of the contents as well as vibration thereof.

It should also be noted that the collet means has the beneficial effect as seen in FIG. 20 of firstly applying side pressure to the outer surface of container means 72 as the support member 230 moves downwardly and urges the collet means and the cartridge supported thereby downwardly against the force of spring 126. This particular coaction ensures that the mixing device firstly applies peripheral pressure to the cartridge before the contents of the cartridge are subjected to compression, thereby preventing undue distortion of the walls of the containers means 72 .of the cartridge when the contents thereof are under pressure and being mixed, and even causing a slight reduction in the internal diameter of the cartridge so that the contents will be loosely contained after pressure is released and the contents may then be easily expelled without jamming against the sides of the cartridge. An air space exists therefore around the contents.

Referring now to FIG. 22, after the mixing of the contents of the cartridge has taken place, the removing member may be moved downwardly by applying manual pressure to the upper surface of portion 262 thereof to thereby move the sharpened lower end 258 of the removing member through the flexible material of the collapsed container means 80. After the enlarged sharpened lower .end has passed through the material, release of the removing member will cause it to move back upwardly under the influence of spring 270, and subsequent movement of the crosshead upwardly will carry the components into the position shown in FIG. 23 so as to effect removal of the collapsed container means from the cartridge. The cartridge then contains the finished amalgam with the inner container means 80 removed therefrom. The opposite closed end of the cartridge may then be suitably cut off for use of the cartridge in a dental instrument as hereinafter described. 1

Referring now to FIGS. 24 through 31 inclusive, a modified form of dental instrument according to the present invention is illustrated. This instrument includes a housing means indicated generally by reference numeral 280 which may comprise two members 282 and 284 which have the opposite edges thereof interconnected with one another as by small screws 285 as illustrated in FIG. 30, the two members each defining substantially half of the complete housing.

An input shaft 290 is provided with a squared end portion 292 adapted to be received within a squared socket provided in the end of a flexible drive means 294 which may be driven by any suitable power means such as an electric motor or the like. It should be understood that the electric drive means for the instrument may be operated by any suitable switch (not shown) which may be operated either by hand or by foot as desired.

Input shaft 290 is rotatably journalled within bearings provided in a boss portion 296 of the housing and a support portion 298 extending inwardly of the housing. A worm gear 300 is mounted on shaft 290 for rotation therewith and meshes with a gear 302 which in turn is fixed to a shaft 304 extending transversely of the housing and having the opposite ends thereof rotatably supported within suitable bearing means mounted within bosses 306 and 308 extending inwardly from the housing members 282 and 284 respectively.

A disc-like driving member 310 is fixed to shaft 304 by means of a set screw 311. Member 310 is provided with an irregular outer surface 312 which may be substantially sinusoidal in shape, and a recess cam portion 314 is provided for a purpose hereinafter described.

The outer surface of member 310 is adapted to engage the rear end of a connecting member 316 which is slidably supported within suitable apertures provided in wall portions 318 and 320 of housing member 284. The outer end of connecting member 316 terminates in two depending spaced ears 322 and 324 disposed in parallel relationship to one another and supporting a pin member 326 between lower portions of the ears.

Connecting member 316 includes a depending portion 330 as seen most clearly in FIG. 24 which is connected with one end of a tension spring 332 the opposite end of which is connected with a connecting lug 334 extending from the wall portion 318 of the housing means. This spring 332 normally tends to bias the connecting member to the right as seen in FIG. 24 to urge the rear portion of the connecting member into engagement with the outer surface of member 310.

An elongated flat operating member 340 is formed of a suitable flexible material such as spring steel or the like and is of sufficient flexibility to permit ready bending thereof. The rear end portion 342 of operating member 340 is clamped between portions of the housing by clamping means 344. The opposite end of operating member 340 includes a pair of depending ears 346 and 348 as seen most clearly in FIG. 31, these ears serving to pivotally support a plunger 350 of generally cylindrical configuration, the upper end of plunger 350 including the normally directed portion 351 extending through suitable slots provided in the ears and having portions 352 secured to opposite ends thereof for retaining it in operative position. One of the slots 346 is provided in ear 346 as seen in FIG. 24, it being understood that a similar slot is provided in the opposite ear 348.

The plunger is guided by' and slidably supported within a bore provided in a boss portion 353 extending upwardly from the wall portion 354 of the housing.

Referring again particularly to FIGS. 24 and 25, a gear member 360 is fixed to the input shaft 290, this gear member having a single tooth 360' as seen most clearly in FIG. 28, the gear member 360 being adapted to mesh with a gear 362 fixed to a shaft 364 journalled for rotation within suitable holes provided in wall portions 366 and 368 of the housing.

Shaft 364 is connected by means ofa universal joint 370 with a shaft 372 so that it may slightly change directions as seen in FIG. 25. Shaft 372 is rotatably supported within a bearing provided in a boss 374 provided on the housing, shaft 372 terminating in a bevel gear 376.

As seen most clearly in FIG. 27, bevel gear 376 meshes with a bevel gear 378 which is formed on a stub shaft 380 having a flange 382 extending radially outwardly from the lower portion thereof. This stub shaft is rotatably supported within the housing portion 354 and is retained in operative position by a snap ring 384. A squared recess 386 is provided in the 'undersurface of stub shaft 380 for receiving a portion of the feed means hereinafter described.

The feed means of this form of the dental instrument is supported by a depending pair of body portions 390 and 392, the feed means including a body means 400 which is adapted to snap into place and to be clamped in the operative position illustrated in FIG. 24 by the spaced body portions. Body means 400 includes a depending working tip 402 having a substantially cylindrical bore 404 formed therethrough, this bore being adapted to receive the plunger 350 previously described.

The construction of the feed means may be most clearly understood from an inspection of FIGS. 32 34 inclusive which illustrates the feed means in association with a jig fixture for assembling and disassembling portions of the feed means with respect to one another. The body means 400 includes a pair of adjacent cavities 408 and 410 which are in communication with one another by a narrow substantially vertically extending slot 409, it being noted that both of these cavities open upwardly but are closed at the bottom thereof.

A generally cylindrical recess 412 is provided in body means 400 and a minor portion thereof is in communication with the cavity 408. This recess 412 receives an anchor end portion 414 having an enlarged portion 424 at the lower end thereof which fits snugly therewithin recess 412, ene portion 414 comprising one end of an elongated flexible member 416 which is looped within the recess 408, then passes through the narrow slot 409 with a snug fit therewith, and thence is looped within the recess 410 such that the opposite end 418 of the elongated member 416 is received within a slot provided in a shaft 420 the upper end of which is squared and which is received within the squared recess 386 previously described. The lower end of shaft 420 is provided with an enlarged portion 424 adapted to be received within a hole 426 disposed within the body means in the central lower portion of recess 410 for retaining the shaft 420 in operative position with respect to the body means and yet permitting rotation of this shaft.

It will be apparent that the interconnection between shaft 420 and the stub shaft 380 is such that a power drive is applied to the end portion 418 of the elongated flexible member 416 whereby this member may be wound up on the shaft 420 so as to close the loop of this shaft which is disposed within recess 408 of the body means.

When it is desired to employ the instrument illustrated in FIGS. 24 31 inclusive, the feed means is initially assembled in the full line position illustrated in FIG. 26 wherein the flexible member 416 is looped within recess 408 such that it is in contact with the walls of the recess so as to receive a body 428 of finished amalgam ready to be inserted in a tooth cavity. The components are then in the operative position illustrated in FIG. 24.

A suitable switch is then actuated so as to provide power drive to the input shaft 290 which causes member 310 to rotate. As member 310 rotates, the connecting member 316 will initially be. moved to the left as seen in FIG. 24, and as this member moves to the left, the operating member 340 is forced downwardly into 

1. A dental instrument for applying a filling material to a tooth cavity, including a housing, a detachable working tip provided at one end of the housing, and having a bore extending therethrough, a container pivotably mounted in the housing for retaining a supply of the filling material, a first spring-loaded plunger for forcing filling material from the container to the bore in the working tip, a second spring-loaded plunger, a push knob having a driving connection with said second plunger for moving such second plunger against the spring pressure and forcing filling material along the bore from the said one end, and locking means coupled to the push knob for preventing the first plunger forcing material into the bore in the working tip when the second plunger is forcing the said material along the bore.
 2. A dental instrument as claimed in claim 1, wherein the locking means comprises a pivotable cam adapted to engage with both a projection on the said push knob and a rack gear directly connected to the first plunger.
 3. A dental instrument as claimed in claim 2, including a second push knob, said second push knob being provided on the first plunger for moving the first plunger from the container against the spring pressure.
 4. In a dental instrument for applying a filling material to tooth cavities, a hollow working tip, chargeable with the filling material and through one end of which the filling material is extruded into the cavity to be filled, a vibratory extrusion plunger displaceable axially in said working tip, a power driven vibrator connected operatively to said plunger, and digitally controlled means to apply an extrusion movement of translation to the plunger during vibration of the plunger by the said vibrator.
 5. In a dental instrument for applying a filling material to tooth cavities, a working tip, digitally actuated means to extrude filling material through the tip into the tooth cavity to be filled, and power driven means constantly operating to impact the filling material into the cavity during the extrusion of the material through the tip by the said digitally actuated means.
 6. A dental instrument for applying a filling material to tooth cavities, comprising a housing, a tubular working tip chargeable with the filling material and supported in, and projecting beyond, one end of the housing, a power driven vibrator carried by the housing, an extrusion plunger positioned to apply extrusion pressure to the material in the working tip, digitally controlled means to effect relative displacement of said plunger and working tip for extruding material from the tip into the cavity to be filled, and means maintaining a permanent transmission of vibration to said plunger from said vibrator during the said digitally controlled relative displacement of the plunger and working tip.
 7. A dental instrument as claimed in claim 6, wherein said digitally controlled means includes a slider adapted to apply a push-feed to said plunger to extrude the material through said tip, and wherein said push-feed is transmitted from said slider to said plunger via said vibrator.
 8. A dental instrument as claimed in claim 7, wherein said vibrator and means transmitting vibration to the plunger are mounted for movement of translation along said housing, and wherein said slider carries an abutment having a push-feed displacement engagement with said vibrator.
 9. In a deNtal instrument for applying a filling material to tooth cavities, a working tip, digitally actuated means to extrude filling material through the tip into the tooth cavity to be filled, power driven means constantly operating to impact the material into the cavity during the extrusion of the material through the tip by the said digitally actuated means, a housing from one end of which projects said tip, a compartment with said housing adapted to be charged with the filling material, an extrusion passage connecting the inner end of the tip of said compartment, extruding means with said compartment to extrude the said material along said passage into said tip, a driver for said latter mentioned extruding means, stop means preventing said driver operating during extrusion of material through said tip, and means controlled by said digitally actuated means to free said driver to actuate said extruding means.
 10. A dental instrument as claimed in claim 9, wherein said digitally actuated means comprises a slider adapted in one endwise direction of movement relative to the housing, to produce a push-feed of the material through said tip, and wherein said extruding means with said compartment comprises a plunger displaceable axially along said compartment, spring means loading said plunger in the extruding direction, said stop means comprising a trigger device preventing reassertion of said spring means during extrusion of material into a tooth cavity, and actuated by said slider to free said spring means upon endwise movement of said slider in the reverse direction.
 11. A dental instrument as claimed in claim 10, wherein said compartment is formed with a wall part displaceable to an open position for reloading said compartment and wherein said plunger displaceable along said compartment is carried by a spring loaded rod, said rod being provided with means to pull the plunger to a starting position at one end of said compartment against the influence of said spring means.
 12. A dental instrument for applying filling material to a tooth cavity, comprising a housing, a tubular working tip at one end detachably engaged in one end of said housing, the other end of the tip comprising a free end projecting beyond the housing for engagement with the work, said first mentioned end of the tip being formed as a head bored in continuity with said tip, a plunger vibratable in the bore of said head, a vibrator carried by the housing and to which said plunger is connected for receiving vibration, and digitally actuated means to apply a movement of translation of the said plunger towards the free end of said plunger while the plunger is being vibrated by said vibrator.
 13. A dental instrument including housing means, a working tip supported by said housing means, said working tip being tubular and having a bore formed therethrough, a plunger mounted for reciprocatory movement through the bore of said working tip, operating means to advance and retract said plunger means with respect to the working tip, vibrator means for vibrating said plunger, feed means to feed amalgam to said working tip, said feed means including storage means for receiving a reserve supply of amalgam, and separate transfer means to transfer amalgam from said storage means to said working tip.
 14. Apparatus as defined in claim 13 wherein said plunger has a relatively snug fit within the bore in said working tip, said plunger being resiliently urged to a retracted position away from the outer end of said working tip.
 15. Apparatus as defined in claim 13 wherein both said operating means and said vibrator means are power operated.
 16. Apparatus as defined in claim 13 wherein said feed means includes a body means defining a cavity for receiving dental amalgam material, said cavity being in communication with said working tip, a flexible elongated member disposed within said cavity in surrounding relationship to amalgam material in said cavity, and means for moving said flexible elongated member to displace saId amalgam material so as to be moved through said working tip upon reciprocation of said plunger.
 17. Apparatus as defined in claim 16 wherein said flexible elongated member is removably mounted with respect to said body means and is anchored at one end thereof to said body means, said body means defining a second cavity and a slot connecting said first and second cavities, said elongated member extending through said slot, said means for moving said elongated member comprising drive means operatively connected with the opposite end of said elongated member.
 18. Apparatus as defined in claim 17 wherein said drive means for the feed means is adapted to move the flexible elongated member of the feed means in incremental steps in timed relation to the movement of said plunger.
 19. Apparatus as defined in claim 16 including an operating member pivotally connected with said plunger said operating member being mounted for swinging movement with respect to said housing means, a connecting member operatively connected with said operating member, said connecting member in turn being in engagement with cam means adapted to control the movement of said connecting member, and resilient means normally biasing said connecting member toward said cam means.
 20. Apparatus as defined in claim 19 wherein said cam means includes portions causing advancing and retracting movements of the connecting member and the associated operating member and plunger, said cam means also including an irregular outer surface adapted to cause vibration of said plunger.
 21. Apparatus as defined in claim 19 wherein said connecting member has a slidable contacting interconnection with said operating member.
 22. Apparatus as defined in claim 13 including an operating member pivotally connected with said plunger, a connecting member slidably interconnected with said operating member for causing movement thereof, said operating means including a power-operated cam means engaging said connecting member, said cam means including portions for advancing and retracting said plunger through the intermediary of said connecting member and said operating member, said cam means also including an irregular outer surface adapted to cause vibration of said plunger, means normally biasing said connecting member into engagement with said cam means, said feed means including a body means defining two adjacent cavities interconnecting with one another by a slot, one of said cavities being adapted to receive a dental amalgam material, a flexible elongated member being anchored at one end thereof and disposed in said first cavity about amalgam material disposed therewithin and extending through said slot into the other cavity, the opposite end of said elongated flexible member being operatively connected with a drive means, said drive means in turn being operatively connected with a power drive means, said drive means being adapted to cause incremental movement of said flexible elongated member in timed relation to the movement of said plunger so as to move the flexible elongated member into the path of said plunger for movement through said hollow tip.
 23. Apparatus as defined in claim 13 wherein said storage means of the feed means includes cartridge receiving means for receving a cartridge having a dental amalgam material therewithin, a piston slidably supported by said housing and adapted to enter a cartridge supported by said cartridge receiving means, drive means for moving said piston relative to said cartridge receiving means, and auger feed means for receiving material from said piston feed means, said auger feed means feeding material into position for engagement by said plunger.
 24. Apparatus as defined in claim 23 wherein said drive means for said piston includes an arrangement for incrementally moving said piston in timed relationship to movements of said plunger.
 25. Apparatus as defined in claim 24 wherein said incremental drive means includes a ratchet and pawl arrangement for providing a one-Way drive connection to said piston.
 26. Apparatus as defined in claim 25 including an operating member pivotally connected with said plunger, a connecting member slidably interconnected with said operating member, said operating means including cam means in engagement with said connecting member, means normally biasing said connecting member into engagement with said cam means, said cam means being power operated, and a power-operated drive connection being provided for said auger feed means.
 27. Apparatus as defined in claim 23 wherein said cartridge receiving means includes a pivotally mounted portion, and a recess being provided in said pivotally mounted portion for accurately positioning a cartridge therewithin.
 28. Apparatus as defined in claim 13 wherein said plunger means is operatively connected with a piston, said piston being mounted for reciprocation within said housing, and means for applying fluid pressure to opposite sides of said piston to cause reciprocation thereof during operation of the apparatus.
 29. Apparatus as defined in claim 28 wherein said means for applying fluid to opposite sides of said piston includes valve means and a plurality of passages providing communication with opposite sides of said piston, said valve means being adapted to control the flow of fluid pressure through said passages.
 30. Apparatus as defined in claim 13 wherein the storage means of said feed means includes cartridge receiving means for receiving a cartridge having dental amalgam material therein, means for applying fluid pressure to one end of said storage means for forcing amalgam material from said cartridge, auger feed means for receiving material discharged from said cartridge and for feeding the material into the path of said plunger means for movement through said working tip, valve control means for controlling the flow of fluid pressure, said operating means including operating means for operating both the plunger and said auger feed means, and control means for controlling the operation of said valve means as well as said operating means.
 31. Apparatus as defined in claim 30 wherein said power-operating means is drivingly connected with said auger means for providing substantially continuous operation of said auger means.
 32. Apparatus as defined in claim 30 wherein said power-operating means includes a pair of operating cams, a connecting member normally biased into engagement with one of said cam means, said connecting member being operatively connected with an operating member which in turn is pivotally connected with said plunger means.
 33. Apparatus as defined in claim 32 wherein said cam means is movably mounted upon a shaft, said shaft comprising a portion of said power-operating means, means normally biasing said cam means in one direction with respect to said shaft, said control means including a finger-operated portion, said finger-operated portion being operatively interconnected with said cam means for controlling the position of said cam means with respect to said shaft.
 34. Apparatus as defined in claim 33 wherein one of said cam means has an irregular surface formed completely around the outer surface thereof, while the other of said cam means has an irregular surface formed partly around the outer surface thereof and a relatively smooth surface formed around the remaining outer portion thereof.
 35. Apparatus as defined in claim 30 wherein said cartridge-receiving means includes a pivotally mounted portion having a recess therein for receiving the flange of a cartridge for accurately positioning the cartridge with respect to said pivotally mounted portion.
 36. A combined dispenser and packer for amalgam into a cavity in a tooth comprising, a housing, an amalgam container mounted on the forward end of said housing, a generally cylindrical receiver chamber removably mounted adjacent said container, means for expelling amalgam from said container into said receiver chamber, and means for ejecting amalgam from saId receiver into the cavity, said ejecting means including a packer member removably mounted in said receiver chamber forcing the amalgam into the cavity and packing the amalgam in the cavity.
 37. A dental instrument comprising, a housing, supply means on said housing for holding a supply of amalgam, a receiver chamber on said housing, means for expelling amalgam into said receiver chamber from said supply means, a packer element having a packing tip in said receiver chamber, means for moving said packer means with respect to said receiver chamber to project said packer tip into operative position while ejecting said amalgam, and vibrator means for vibrating said packer element.
 38. A hand held dental instrument for dispensing an amalgam into a cavity of a tooth and packing the amalgam therein comprising, a storage means on the instrument containing a supply of amalgam, feeding means in association with the storage means feeding the amalgam into a chamber, and means in the chamber discharging the amalgam from the chamber into the cavity and packing the amalgam in the cavity.
 39. A hand held dental instrument for dispensing an amalgam into a cavity of a tooth and packing the amalgam therein comprising, a storage means on the instrument containing a supply of amalgam, feeding means in association with the storage means feeding the amalgam into a chamber, means in the chamber discharging the amalgam from the chamber into the cavity and packing the amalgam in the cavity, and vibrating means on the instrument vibrating the last named means during the packing of the amalgam. 